Rho-kinase controls cell shape changes during cytokinesis
Rho-kinase controls cell shape changes during cytokinesis
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DOI：
10.1016/j.cub.2005.12.043
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发表时间：
2006-02-21
期刊：
影响因子：
9.2
通讯作者：
O'Farrell, PH
中科院分区：
文献类型：
--
作者：
Hickson, GRX;Echard, A;O'Farrell, PH
背景：动物细胞胞质分裂的特点是一系列剧烈的皮质重排。这些如何协调并与有丝分裂结合在很大程度上尚不清楚。为了探索胞质分裂的启动，我们重点关注了最早的细胞形状变化，即细胞伸长，这种变化发生在后期 B 期间和细胞分裂皱褶之前。结果：在果蝇 S2 细胞中使用 RNAi 和实时视频显微镜，我们发现 Rho 激酶 (Rok) 和肌球蛋白 II 与后期细胞伸长有关。 rok RNAi 减少了赤道肌球蛋白 II 的募集，阻止了细胞伸长，并引起显着的纺锤体缺陷，即纺锤体极与不屈服的细胞皮层碰撞，极间微管在继续延伸时向外弯曲。用 Latrunculin A 破坏肌动蛋白细胞骨架，消除皮质刚性，抑制纺锤体缺陷。 rok RNAi 也会影响犁沟，使犁沟延迟、减慢，有时甚至扭曲，严重时甚至完全受阻。肌球蛋白磷酸酶（肌球蛋白 II 激活的拮抗剂）的肌球蛋白结合亚基 (Mbs) 的共耗竭仅部分抑制了细胞伸长缺陷和皱纹延迟，但阻止了长期 rok RNAi 诱导的胞质分裂失败。通过对 Rho 通路中其他基因（例如 pebble、racGAP50C 和 diaphanous）进行 RNAi，突显了细胞伸长对 Rok 耗竭的显着敏感性，这些基因对犁沟有深远影响，但对伸长影响较小。 胞质分裂，并表明独特的调节途径促进细胞伸长。
Background: Animal cell cytokinesis is characterized by a sequence of dramatic cortical rearrangements. How these are coordinated and coupled with mitosis is largely unknown. To explore the initiation of cytokinesis, we focused on the earliest cell shape change, cell elongation, which occurs during anaphase B and prior to cytokinetic furrowing.Results: Using RNAi and live video microscopy in Drosophila S2 cells, we implicate Rho-kinase (Rok) and myosin II in anaphase cell elongation. rok RNAi decreased equatorial myosin II recruitment, prevented cell elongation, and caused a remarkable spindle defect where the spindle poles collided with an unyielding cell cortex and the interpolar microtubules buckled outward as they continued to extend. Disruption of the actin cytoskeleton with Latrunculin A, which abolishes cortical rigidity, suppressed the spindle defect. rok RNAi also affected furrowing, which was delayed and slowed, sometimes distorted, and in severe cases blocked altogether. Co-depletion of the myosin binding subunit (Mbs) of myosin phosphatase, an antagonist of myosin II activation, only partially suppressed the cell-elongation defect and the furrowing delay, but prevented cytokinesis failures induced by prolonged rok RNAi. The marked sensitivity of cell elongation to Rok depletion was highlighted by RNAi to other genes in the Rho pathway, such as pebble, racGAP50C, and diaphanous, which had profound effects on furrowing but lesser effects on elongation.Conclusions: We show that cortical changes underlying cell elongation are more sensitive to depletion of Rok and myosin II, in comparison to other regulators of cytokinesis, and suggest that a distinct regulatory pathway promotes cell elongation.